Explanation:

‘how many goals scored’ is written as ‘5 3 9 7’;
‘many more matches’ is written as  ‘9 8 2’;
and ‘he scored five’ is written as ‘1 6 3’. 

here 9 is code for many
and 3 is code for scored
5 7 is code for how and  goals
So 5 or 7 can be the code for goals